The present invention relates to technique which can be effectively applied to a display driver control circuit for driving a display device such as a liquid crystal display panel and particularly to technique which can be effectively applied to a display driver control circuit of a display panel of a small size information terminal, for example, a mobile phone
In these years, a dot matrix type liquid crystal display panel where a plurality of display pixels are allocated in two dimensions in the shape of matrix is generally used as a display device of mobile electronic devices such as mobile phones and PDA (Personal Digital Assistants). In this display device, a liquid crystal display control circuit (liquid crystal controller) formed on a semiconductor integrated circuit for display control of the liquid crystal display panel and a driver for driving the liquid crystal display panel or a liquid crystal display driver control circuit (liquid crystal controller driver IC) comprising the driver are mounted.
The liquid crystal controller driver IC for driving the liquid crystal display panel provided in such mobile electronic devices is required to have small chip area and lower power consumption from the property of mounting into mobile terminals. The liquid crystal controller driver used in the system including a small-size liquid display panel such as mobile phones generally is configured to comprise a display memory having the capacity larger than the amount of display data of one display area of the display panel and to read the display data for every one horizontal line after once storing this data in the display memory in order to convert the data to gradation voltage and to output to the display panel.
A liquid crystal controller driver comprising a display memory is disclosed in the invention, for example, as the patent reference 1 (Japanese Laid-Open Patent Publication No. Hei 9(1997)-281933).